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关键词： MMC-SST   PEEK   Surface partial discharge   DC voltage  

摘要： Modular multilevel converters (MMCs) have been utilized in solid-state transformers (SSTs). With the increasing demand in high-voltage power module in MMC-SST, press-pack IGBTs are very promising. The poly-ether-ether-ketone (PEEK) frame is utilized in the submodules of press-pack IGBT to withstand the high voltage. The electric field simulation in this paper reveals that electric field concentrates on the surface of the PEEK frame. Thus, the surface partial discharge characteristics under direct current (DC) voltage is investigated by the developed test bench. The results show that surface partial discharge model of PEEK sample has polarity effect. Under positive and negative polarity voltage, the average discharge quantity, maximum discharge quantity and discharge repetition rate of the PEEK sample all increase with the voltage amplitude. Moreover, the front time of the surface partial discharge waveform reaches 20 ns, and its frequency spectrum is concentrated in range of 10-20 MHz.

关键词： AC-DC power converters   Power electronics   Pulse-width modulation converters   Submarine battery  

摘要： This innovative charger-discharger utilizing the technology of IGBT, designed for lead-acid submarine batteries, is discussed in the present manuscript. Within the system, a bidirectional DC-DC converter links the Battery-Ultra Capacitor system, ensuring Depth of Charge and State of Charge are controlled very precisely to avoid sulfation. Over 12 months of field tests, IGBT chargers succeeded in obtaining 93 % charge efficiency;at its turn, the one with linear charging, provided by traditional rectifiers, for instance, was already 85 %, meaning it literally snatched huge energy savings and was cost-wise beneficial. The system showed a better thermal stability at just 2.3 degrees C standard deviation fluctuation. As per the regression, if the efficiency is improved by 1 %, the life of the battery is extended to nearly 0.53 months. The result was further confirmed by ANOVA, and the fall of batteries was predicted with 92 % accuracy with the help of a Random Forest model. As such, on balance of performance, cost, and reliability, the most appropriate technology for the submarine application is that of the IGBT rather than the SiC MOSFETs or GaN transistors. It conserves power and gas generation for improved operational efficiency and higher battery life, and improves overall sustainability.

关键词： Insulated gate bipolar transistors   Monitoring   Short-circuit currents   Logic gates   Wires   Bonding   Aging   Bonding wire   condition monitoring   health state   IGBT module   short-circuit current   temperature criterion  

摘要： The bonding wires and busbars in IGBT modules may have open points and breaks during long-term use, causing changes in short-circuit current. The health status of the IGBT module can be analyzed by detecting and judging the short-circuit current. The self-excited short circuit monitoring technology controls the gate voltage to cause small current short circuits in the IGBT. By detecting the magnitude of the self-excited short circuit current, the damage to the IGBT module bonding wire is determined. The accuracy of the monitoring results of this method is affected by changes in device junction temperature. Based on the application scenario of urban rail traction inverters, this article proposes an improved temperature criterion for the self-excited short-circuit monitoring method. The multidimensional relationship between IGBT module short circuit current, health level, and temperature changes is analyzed. The temperature ranges for self-excited short circuit detection based on the actual operating conditions of urban rail inverter is studied, and the driving module status judgment is set to only determine the health status of effective data points within the temperature range. This method can suppress the influence of IGBT working temperature on short-circuit condition detection and improve the accuracy of the criterion. At last, a current detection experiment was conducted to simulate the fracture of bonding wires, verifying the effectiveness of the proposed method.

关键词： RC-IGBT   Impact ionization   Snapback effect   Silicon germanium   Tunneling  

摘要： In this study, two new structures are proposed for reverse-conducting insulated gate bipolar transistors (RC-IGBT) that effectively prevent snapback by relocating the N-collectors and utilizing silicon-germanium in the collector region of each device. The forward mode of the proposed structures shows IC- VC characteristics without snapback, since the position of the N-collector is changed to prevent electron extraction. In the reverse mode, the silicon-germanium induces currents through tunneling and impacts the ionization mechanisms. Importantly, the proposed structures generate a stable current value even if there are errors in the length of the N-collector during ion implantation, which enhances the reliability of the device. In addition, the proposed structures exhibit similar values for the breakdown voltage at around 700 V and the turn-on and turn-off losses when compared to the conventional RC-IGBT. Thus, this paper improves the reliability of RC-IGBTs by mitigating the snapback effect while maintaining their unique electrical properties.

关键词： Insulation   Temperature   Electrostatics   Electric breakdown   Temperature measurement   Electric potential   Insulated gate bipolar transistors   Electrically insulating properties   packaging insulation   silicone gel   thermal stability  

摘要： We report that trifluoropropyl/phenyl is introduced into silicone gel to prepare a novel silicone gel with enhanced electrically insulating properties, and the influence mechanism of different side groups on the electrically insulating properties of silicone gel is analyzed by molecular simulation and experimental comparison. The results show that silicone gel with only high-electron-affinity phenyl has the strongest breakdown strength, which is 32.87 kV/mm. The introduction of strongly polar- ized trifluoropropyl results in the dielectric constant at the power frequency of silicone gel reaching 5.1673, which is 1.88 times that of pure silicone gel. More importantly, the dielectric constant at the power frequency condition and the breakdown strength of the modified silicone gel with trifluoropropyl and phenyl simultaneously increase to 3.0725 and 29.42 kV/mm, respectively. Meanwhile, it also exhibits excellent thermal stability. This work has important information for the development of novel silicone gel with high electrically insulating properties.

关键词： 碳中和   经济增长   碳中和能力   生态碳汇   最优控制  

摘要： 碳中和对人类社会可持续发展具有重要意义， 而碳中和技术与生态碳汇是影响碳中和能力的重要因素. 本文首先将这两种因素以及碳中和目标中明确的时间节点纳入考虑， 构建了碳中和目标影响下的有限时域经济增长模型， 然后运用最优控制理论获得了该问题最优解的显式表达式， 并在此基础上分析了最优消费、投资、资本存量、碳中和能力的性质， 最后基于理论分析与数值仿真结果， 提出了相关政策建议. 研究表明， 各国需根据自身禀赋以及目标资本存量等因素， 制定与之相匹配的碳中和目标; 不同国家或者同一国家的不同地区， 应当根据碳中和过程所处的不同阶段选择不同技术水平的碳中和投资; 与通常预期不同的是， 碳中和能力路径可能随碳中和技术投资产出弹性的上升而下降; 在接近碳中和时间节点时碳中和投资可能出现“反常”现象.

标准号: GB/T 24625-2024

摘要： 本文件规定了变频器供电的三相或多相电励磁同步电动机及永磁同步电动机定额、结构型式、性能要求、冷却方法、试验方法及验收规则，包含对变频器的要求。 本文件适用于变频器驱动的同步电动机。

关键词： 矿用变频器   高频电路模型   损耗模型   电热耦合  

摘要： 矿用变频器一般工作在密闭空间下，电热耦合效应显著，易导致热退化和热失效。另外，矿用变频器和电机通常采用长电缆连接，需要考虑电缆带来的高频负面效应。本研究以630kW/1140V四象限矿用变频器为对象，建立其一体化电热耦合模型并对其相关特性进行研究分析。首先，建立了矿用变频器的高频电路模型。其次，研究各功率器件损耗受温度影响的机理，分析了部分损耗随温度的非线性关系，推导了各损耗随温度变化的解析模型。最后，分析了高频电路模型、损耗模型以及温度场模型之间的耦合关系，建立了矿用变频器的一体化电热耦合模型。耦合仿真结果表明了电热耦合建模的必要性，实验和仿真结果最大误差仅为0.9℃，验证了所建模型的准确性。

关键词： Insulated gate bipolar transistors   Magnetic circuits   Logic gates   Mathematical models   Integrated circuit modeling   Analytical models   Magnetic analysis   Burst pulse interference   current spectrum   field-circuit coupling   insulated-gate bipolar transistor (IGBT)   magnetic field interference (MFI)   three-phase inverter circuit  

摘要： It is well known that insulated-gate bipolar transistors (IGBTs) are often operated in complex electromagnetic environments, however, there are few researches on magnetic field interference (MFI) effects on their performance, as well as reliability for high power applications. Here, we present one hybrid approach that integrates computational magnetics method and circuit modeling technique to investigate the burst pulse MFI on the IGBT module. Such IGBT module is at first represented by an equivalent circuit model, enabling subsequent magnetic field simulations targeting at its susceptible regions. The simulated magnetic field distribution at different time steps, the distribution of eddy current, flux density and temperature rise in the IGBT module induced by the MFI source are all predicted. Further, experimental validation is conducted to verify the accuracy of the simulation and modeling analyses. It is believed that this research will be very useful for understanding the MFI mechanism in the IGBT module, enhancing their reliability and performance in particular for high-power applications.